For an explanation, see the main splats page

The principles of gases

• Around 1620, Jan Baptista van Helmont coined the new word 'gas', taking it from the Flemish word for 'chaos', suggesting he had some notion of what gases are.

• In 1661 Robert Boyle published his 'Sceptical Chymist' and stated his law for ideal gases relating volume to pressure, and made a number of other key points.

• In his 'Sceptical Chymist', Robert Boyle made reference to chemical elements, acids and alkalis, and offered a corpuscular theory of matter, all in one year.

• An ideal gas obeys the law described in the gas equation. Real gases approximate reasonably well to Boyle's law, Charles' Law and the combined gas law.

• The first person to propose that gases were made of particles was Daniel Bernoulli, who realized that assuming a gas made of particles explained its behaviour.

• The behaviour of gases may be explained by using the kinetic molecular theory which considers the gas molecules as independent particles, able to move freely.

• In 1848, James Joule calculated the average velocity of gas molecules from kinetic theory. It contained the first numerical results from the kinetic theory.

• The diffusion of gases obeys Graham's law of diffusion, which says that the square root of the density of the gas is inversely proportional to its velocity.

• The reactions between gases follow Gay-Lussac's law, which states that the volume ratios of the reactants and the products will involve small whole numbers.

• Avogadro's hypothesis proposed that equal volumes of gas under the same conditions of temperature and pressure, contained the same number of molecules.

• In 1772, Joseph Priestley discovered that the volume of air decreases when an electric spark passes through it, but did not explain the effect.

• Avogadro's constant is the number of molecules of a compound with a mass in grams equal to the molecular weight, and as a gas, occupies 22.4 litres at STP.

• In the 1890s, Rayleigh found that nitrogen prepared from air had a different density from nitrogen which was prepared chemically. The difference was argon.

• In 1798, Humphry Davy was involved in treating people with gases. During this work, he saw the effects of laughing gas (nitrous oxide), and wrote about them.

This file is http://members.ozemail.com.au/~macinnis/scifun/, first created on February 17, 2009. Last recorded revision (well I get lazy and forget sometimes!) was on February 17, 2009.

©The author of this work is Peter Macinnis, who asserts his sole right to the product as it is packaged here, recognising that many of the ideas are common. You are free to use this as a model to do your own version. Copies of this whole file or site may be made and stored or printed for personal or educational use. You can contact me at macinnis@ozemail.com.au, but only if you add my first name to the front of that email address -- this is a low-tech way of making it harder to harvest the e-mail address I actually read.
This site had 219,000 hits on the index page from 1999 to January 2007 and an unknown number on other pages. In January 2007, a combined counter was placed on all of the pages, counting page hits which now total